Gear boxes are used in many different drivetrain applications within a vehicle, including transfer case and inverted portal axle applications. The gear boxes include components such as gears, bearings, thrust washers, shafts, etc. that are housed within a gear housing. These components need to be sufficiently lubricated during operation to minimize fatigue and wear.
Traditionally, lubrication has been provided by a “splash” lubrication method. In the “splash” lubrication method oil is flung or splashed about within the gear housing as a result of various movements of the components in the gear box. This method can present difficulties with applications that have large vertical separation between gears, such as in inverted portal axle and transfer case applications. Ensuring an adequate supply of lubrication in such applications is often difficult to achieve. Thus, not all of the gear box components receive a consistent and reliable supply of lubrication, which can lead to premature wear or failure.
Elevated fill levels and trial and error test lab developments have been proposed as solutions to this problem. However, these solutions also have disadvantages. Elevated fill levels often result in churning losses and excessive heat generation, which adversely effects the operation of the gear box. Trial and error test lab developments are often tedious and can lead to long development times.
Thus, there is a need for a simple and effective pumping mechanism for a gear box that can consistently and adequately lubricate gear box components.